The idea that it's cheaper to leave the heating on low all day is a myth "A timer's best as your thermostat turns your heating on and off to keep your home at the temperature you set. "The key thing to understand here is that it's all about the total amount of energy required to heat your home." However, people living in places where it's damp might have to turn the central heating on for longer. Martin added: "There are some engineers who argue that keeping the heating on low with all the radiators on and the boiler down can work as it reduces condensation, which when the heating is turned off collects within the walls, and can help conduct heat outside the home - meaning you lose heat more quickly and so will lose heat more quickly and will use more energy as a result.